A list of dicts tracking the context state. Each
new ContextTracker.callWithContext
pushes a new dict onto this stack for the duration of the
call, making the data available to the function called and restoring the
previous data once it is complete..

A list of dicts tracking the context state. Each
new ContextTracker.callWithContext
pushes a new dict onto this stack for the duration of the
call, making the data available to the function called and restoring the
previous data once it is complete..